Image sensor devices are widely used in various imaging applications and products, such as smart phones, digital cameras, scanners, etc. Typically, an image sensor device uses micro-lenses to condense incident light into color filters when the incident light first enters the image sensor device. However, various dielectric films used in the image sensor device with CMOS technology increase the number of optical paths, and such films are transparent to visible light. Even if the image sensor device includes a grid to block the optical paths from crossing subpixels, the incident light may dissipate (e.g. penetrate into other pixels under the grid), in which a crosstalk issue arises, resulting in signal-to-noise ratio (SNR) degradation.